(ISO 9002 COMPANY)

AutomaticVoltage Regulating

RelayEE 301-M

INSTRUCTION MANUAL

Instruction Manaualfor

AutomaticVoltage Regulating Relay

Type EE 301-M

DOC No. : MK 01 - 702 / ISS.2

EMCO ELECTRONICS

Works : Unit No. 13, "Kedarnath", Tungareshwar Industrial Complex No. 1, Village Sativali,Vasai(E), Dist : Thane - 401208. Tel.:(0250)2481783 / 1804, Fax : (0250)2481087,Email : mumbai@emcoelectronics.org

Office : 302, Vasan Udyog Bhavan, Sanapati Bapat Marg, Opp. Phoenix mill / Big Bazar,Lower Parel(W), Mumbai - 400 013. Tel.:(022)24902283/24923183,Fax : +91-022-24951024, E-mail : office@emcoelectronics.org

South : 15, Wood Street, (1st Floor),Richmond Road, Bangalore - 560 025Office Tel : (080) 557 0215 Fax : +91-80-556 6606

E-mail : emcoblr@bgl.vsnl.net.inVisit us at : www.emcoelectronics.org

C O N T E N S

Sr. No. TITLE PAGE No.

I INTRODUCTION 1

II GENERAL DESCRIPTION 1

III SPECIFICATIONS 1

IV FAMILIARIZATION WITH INDICATIONS / CONTROLS 2

V OPERATION INSTRUCTIONS 4

VI TYPICAL INSPECTION PROCEDURE 5

VII FUNCTIONAL DESCRIPTION OF VARIOUS MODULES 6

VIII FAULT FINDING PROCEDURE 7

IX LINE DROP COMPENSATOR 11

X SUPERVISORY ALARMS OPTION 13

XI LIST OF DRAWING & RECOMMENDED SPARES 14

XII WARRANTY 15

XIII FAULT REPORT FORM 19

I INTRODUCTION

EMCO’s Solid State Voltage Regulating Relay Type EE 301- M is used for regulating thesecondary voltage of power transformer with on-load tap changer . The required dead-bandsettings are set by setting the Nominal value and L & R levels independently. The Time Delaysetting on the front panel eliminates the relay operations for momentary fluctuations of theregulated voltage, thus reducing the number of operations of the tap changer.

When the regulated voltage falls below the specified Under Voltage limit, the control relays areautomatically blocked i.e. there is no voltage correction, and a pair of relay contacts is madeavailable for alarm.

The relay uses all solid state circuitry which increases its reliability and life. The relay is ofmodular construction and the PCBs are plug-in type and can be easily withdrawn from theinstrument for servicing without disturbing the unit. The O/P, I/P connections are made through apolarised connector which enables easy removal of the instrument without disturbing the controlwiring. However all normal precautions/care in handling/storage should be observed as for asensitive electronic instrument.

II GENERAL DESCRIPTION

EMCO ‘s Solid State Voltage Regulating Relay Type EE 301-M is designed for maximumoperational simplicity for regulating the secondary voltage of power transformer with on-load tapchanger. The dead-band (bandwidth) can be set by setting the nominal value (NVA) to the requiredvalue (110V + 10%) and then setting the L & R limits around the NVA within 0.5V to 5V.

The desired time delay can be set on the front panel and the control action will take place only ifthe voltage continues to remain outside the dead-band after the time delay has elapsed. Forvoltage corrections requiring more than one tap change, time delay is initiated again before furthertap change. The relay is reset automatically after the voltage is brought within the selecteddeadband. The time delay is effectively reduced to provide a voltage time integral response of theregulator for repeated short duration voltage fluctuations on the same side of the dead-band.

Operation of the Raise Control Relay is automatically inhibited when the voltage falls below thespecified under voltage limit or it fails. One pair of normally open relay contacts are provided toeffect the tap change during Raise and Lower operation and to trigger an alarm in case of Undervoltage / P.T. fail conditions.

III SPECIFICATIONS :

Auxiliary Supply : 110V / 230V AC + 15% 50Hz, 15VA.

PT Supply (Requlated Voltage) : 110V + 10%, 50Hz, 1.5 VA.

Sensitivity (Dead Band) : 1. Nominal value adjustable (NVA) between and Nominal value Range +10% of 110V and readable on DPM.

2. ‘L’ setting adjustable between 0.5V to 5V above the NVA and readable on DPM.3. ‘R’ Setting adjustable between 0.5V to 5V below the NVA and readable on DPM.4. Actual PT voltage also readable on DPM.

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Time Delay Setting : Fixed (Voltage independent) Time Delay continuouslyadjustable from 10 to 120 seconds.

Time Delay Resetting : Instantaneous resetting with voltage deviationoccurring in opposite direction.

Under voltage Blocking : Internal blocking at 80% of NVA. Restoration at 85%of NVA

Control Relays : One pair of normally open potential free contacts ofrating 5A at 250V AC or 24V DC resistive load foreach Lower, Raise and Under voltage control relays.

Control Operation : Single Pulse operation with 2 seconds (approx.)on-time.

Operating Temperature : 0° - 45° C.

Overall Size : 378 x 146 x 260 mm (HxWxD)

Mounting Details : Panel cutout - 330 x 135 mm,with mounting holes (1/4" Æ x 4 Nos.)@ (360 x 100) + 2mm

Weight : 5kg Approx.

Options : 1) Line drop compensator with resistive and reactivecompensation of either polarity upto 20% andsuitable for operation with 1A/5VA currentTransformer.

2) Normally closed “Auxilliary Supply Fail” relaycontacts.

3) Normally open “Control Fail” relay alarm contactsin case of control failure (i.e. in case of continuous‘L’ or ‘R' command for more than 15 minutes).

4) User defined settings for PT Supply, Time Delay& Undervoltage Blocking

IV. FAMILIARIZATION WITH VARIOUS INDICATIONS / CONTROLS :

A. INDICATIONS

1. Auxiliary Supply “ON” : DPM digits light.

2. ‘L’ Lamp : ‘ON’ whenever the PT Voltage exceeds the 'LOWERVOLTS’ set limit.

3. ‘R’ Lamp : ‘ON’ whenever the PT voltage falls below the ‘RAISEVOLTS’ set limit.

4. UV/PT FAIL Lamp : 'ON’ whenever the PT Voltage falls below the factoryset Under Voltage limit i.e. below 80% of the Nominalvoltage. This lamp will turn-off only when the PT voltage raises above 85% of the Nominal voltage value.This lamp will be ‘ON’, when P.T. supply fails.

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5. 'LR' Lamp : 'ON' When Lower Relay is energised.

6. ‘RR’ Lamp : ‘ON’ When Raise Relay is energised.

7.‘TEST’ Lamp : ‘ON’ When instrument is in “TEST” mode.

B. CONTROLS

1. Power - ON (S1) : This is a toggle switch which when’ON’ suppliesAuxiliary Voltage to the instrument.

2. 'R’ Set (C1) : This is a variable control varying from 0.5V to 5.0V belowNVA setting. This control sets the (lower limit of the PTvoltage below which if the voltage reduces, thencorrective action will be taken by the instrument. Thesetting is to be read on DPM.

3. 'NOM’ Set (C2) : This is a variable control to set the Nominal value ofPT voltage varying between + 10% of 110V. This setting becomes the reference level around which L & Rsetting can be varied. The setting is to be read on theDPM.

4. 'L’ Set (C3) : This is variable control, varying from 0.5V to 5.0Vabove NVA setting. This control sets the upper limit ofthe PT voltage beyond which if the voltage rises,corrective action will be taken by the instrument. Thesetting is to be read on DPM.

5. Time Delay (C4) : Corrective action takes place only after the Time Delayas set by this control has elapsed and the PT Voltagecontinues to ramain outside the set Lower or Raiselimits (but does not fall below the UV limit).

6. Test/Normal Switch (S2) : It selects the Test or Normal mode of operation. In theTest mode, PT Voltage is simulated internally & can bevaried through the Test Control on the front panel. AnLED indication is provided to indicate that theinstrument is in Test mode. In the Test mode, thecontrol relays are “cut off” so that undesired operation ofOLTC is prevented during testing. The voltage ismonitoredon the DPM in PT I/P position. In the Normalmode extemal PT voltage gets connected to theinstrument. This switch must be kept in ‘’Normal” modewhen the instrument is in use.

7. Test Voltage Control (C5) : Simulates PT I/P in Test mode and can be variedfrom OV to 150V AC.

8. Selector Switch (S3) : Selects the voltage setting to be monitored on fhe DPM.It also enables the PT voltage to be read on the DPM.

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NOTE : Before connecting Aux. Supply & PT Supply to the AVR Relay, Check-up following points.

A) Mechanical Damage : Remove the front acrylic cover by loosening thethumbscrews & check for any mechanical damage to the unit.

B) Check all plug-in modules : Open the botton panel & check M1 , M2, M3 &M4 for any damage. Insert them fully inside, to avoid problems due to loosecontact.

C) Aux fuse & P.T. fuse : Note that Aux. fuse is 300mA (20mm) & P.T. fuse is100mA (20mm). Do not interchange these fuses. Check them & replace withgood ones if required.

D) Close the lower bottom panel.

V. OPERATING INSTRUCTION :

1. Connect the PT & Auxiliary Supply to the appropriate wires (3,4) and (1,2)respectively, of the rear panel connector as per Drg. No. 01-MD-30. In caseseparate Auxiliary supply is not available, then the same PT supply can beconnected to both the PT & Auxiliary terminals. Check whether the Normal/Testswitch is in the Normal mode.

2. UNDER VOLTAGE BLOCKING :

This is factory set at 80% of the Nominal voltage. Note that between Blockingand the Release (Restoration), a hysteresis of 5% has been provided i.e. if thePT voltage falls below 80% of the Nominal value limit, UV Relay will operateand block the control action (i.e. RAISE would be inhibited). However, if thevoltage rises again the RAISE control continues to remain inhibited till PT voltagereaches 85% of the Nominal voltage. Blocking (80%) and Restoration (85%)are factory set values, unless the customer has specified other values.

3. TIME DELAY :

This is a variable control with variation from 10 sec. to 120 sec. The actualsetting can be made as required. The corrective action will take place only afterthe set Time Delay interval is elapsed provided the voltage deviation persistseven after the set Time Delay and that the relay is not operating in UV mode.

NOTE : Please note that for the operational safety, RAISE and LOWER relays areinterlocked and hence OLTC will never receive two opposite commandssimultaneously.

4. CONTROL RELAYS :

Connect the respective Lower, Raise and Under voltage NO contacts to operatethe respective contactors.

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VI. TYPICAL INSPECTION PROCEDURE :

1. Connect 110V/230V A.C. Aux. supply to pins (1,2) of the rear panel connector.

2. Turn on the instrument by putting power switch to ‘ON’ position.

3. Make the following settings by changing selector switch :

NOMINAL VALUE 110V

LOWER VOLTS Setting 112V

RAISE VOLTS Setting 108V

TIME-DELAY Setting 30 Sec.

%R & %X Setting ‘0’ %

(in case of relay with LDC)

4. Put the Test/Normal Switch to Test mode and selector switch to PT I/P position.

5. Increase test-control to read PT = 110V.

6. Note that under this condition all the lamps viz. L, R, LR, RR, & UV are OFF.

A. LOWER VOLTS OPERATION CHECK :

1. Increase PT supply by the Test control above 112V (at least 112.5V), ‘L’ Lampshould immediately turn on.

2. The ‘LR’ Control pulse will come on only after 30 sec. from the instant of tumingon of ‘L’ lamp. The control pulse will remain ‘ON’ for 2 sec., after which the TimeDelay of 30 sec. will restart and the control pulse will come again for 2 secs.and the cycle is repeated.

B. RAISE VOLTS OPERATlON CHECK :

1. Reduce PT Supply by the Test control•below 108V (at least 107.5V), but ensurethat it is above UV limit (88V). ‘R’ Lamp should turn ‘on’ immediately.

2. The ‘ RR’ control pulse will come on after 30 sec. from the instant of turning onof ‘R’ Lamp. The control pulse will remain on for 2 sec. after which the T.D. isinitiated again. After another 30 sec., the control pulse will come again for 2sec. and the cycle is repeated.

NOTE: The relays are cut off in the Test mode of operation to prevent any undesirableoperation of the OLTC during testing. However, the lamp indications willindicate the operation of the relays. For checking the relay contacts, the PTI/P should be connected through the rear panel connector (pins 3,4) andTest/Normal switch put in Normal mode. The PT I/P can be varied externallyand the relays are checked as above. The respective N0 contacts will close.

C. UNDER VOLTAGE/PT FAIL OPERATION CHECK :

1. Reduce the PT supply below 88 V, UV lamp will turn-on immediately (underthis condition R lamp wiil also be ‘on’). but Raise control is inhibited.

2. Raise the PT supply above 94V, UV lamp should turn off immediately.

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3. ‘R’ lamp indication however shall remain on, if the PT voltage is still below theRaise setting. The raise control pulse will come on after the set Time Delay.

4. Disconnect extemal PT supply - the UV & R Lamp will turn on immediately. TheUV relay will operate. After restoration of PT supply, the lamp wiil turn ‘off’ & UVrelay will be deenergised.

FUSE REPLACEMENT :

1 After switching power-on, the DPM indication must come. If it does nof come,check whether AUX. fuse on the front panel is properly tightened. If theinstrument still does not work, unscrew the fuse & check if it is open. Replaceit by another fuse of 300mA (20mm).

Once again ensure that the fuse is not loose. The instrument should turn onnow. If the fuse keeps on blowing repeatedly or the instrument does not workinspite of good fuse, proceed to identify the faulty PCB as given in fault findingprocedure VIII.

2 Connect the PT supply and put the Test/Normal switch in Norrnal position. Ifthe Instrument is turning on but you are continuously getting 'R’ and ’UV’indication, check whether PT fuse is loose. If the condition persists even aftertightening PT fuse, remove the same and replace by another 100mA (20mm)fuse. If ‘UV’ and ‘R’ indication still persist, proceed to identify the faulty PCB asgiven in fault-finding procedure VIII.

VII. FUNCTlONAL DESCRIPTlON 0F VARlOUS MODULES :

1. Mains Transformer : This trasnformer is mounted on the rear side railing. Thistakes 230V/110V A.C. and steps it down to 19V, 12V, 5V, 10V A.C. voltagesrequired generating dc power.

2. P.T. Transformer : This is mounted on PCB module M2 which steps down PTinput from 110V A.C. to 3.3V A. C. Which is used for sensing PT voltage.

3. Power Supply Module M1 : This module generates +15V DC, -15V DC,+5V DC & +5V DC (for DPM) required for circuit operation. Three pin regulatorICs 7815, 7915, 7805 are used to give regulated +15V, -15V & +5V D.C.Supplies. The four LEDs mounted on front side of module M1 indicate thepresence of these voltages. If all four LEDs of module M1 are glowing brightly&voltages are as given in TABLE 1 (Page No.9) then this module is OK. If anyoneLED is not glowing or glowing very dim, then proceed as per step No.5 given infault finding procedure VIII.

4. Analog Module M2 : The PT input is stepped down in the ratio 110/3.3. Thisstepped down voltage is rectified. filtered and amplified by IC4 & IC5. Thisvoltage is used for comparison with reference voltage. IC3 generates regulated+10V DC by taking +15VDC as input. This 10V DC rs used as a referencevoltage for comparison. IC2 compares the input signal with L, R, UV set points& generates appropriate L, R or UV signal which are passed on to module M3.

5 Digital Module M3 : This card receives L, R, UV signals from card M2. On

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receiving any of these signals, it generates Time Delay followed by LR, RR & UVcommands for energizing appropriate relay.

6. Relay Module M4 : In this module , relays for L, R, & UV commands are mountedwhich are energized as per commands received from module M3.

7. Digital Panel Meter : The main function of DPM is to display PT input, Nominalsetting, L, R settings through selector switch. This DPM operates on +5V supplywhich is supplied by P.S. Module M1.

VIII. FAULT FINDING procedure :

Before proceeding to fault finding, be familiar with the functions of each module & various testpoints on these modules. Study the nature of fault & try to visualise faulty module. Then Pro-ceed step by step as follows.

Step-1 : Check for any physical damage by opening front doors.

Step-2 : Check the Aux. fuse (300mA) & PT fuse (100mA). If necessary, replacethem. (Do not interchange the fuses). Tighten them properly.

Step-3 : Confirm that all four modules M1, M2, M3 & M4 are inserted fully in thebackside connectors & having proper contacts

Step-4 : Connect 'Aux’ supply & PT supply & Switch ON the unit. If the unit doesnot get switched ON, then check aux. switch.

Step-5 : Open the bottom front cover. Check the four LEDs mounted on moduleM1.If all LEDs are glowing brightly then module M1 is alright. If anyone of theLEDs is not glowing or all LEDs are glowing very dim, then measure voltageson the test points as given in table No.1. If the voltages are not asexpected, then remove other modules M2, M3 & M4. Measure the voltagesagain (or confirm all 4 LEDs are glowing brightly). If voltages are not correctthen replace M1. If the voltages are correct without M2, M3, & M4, it meansM1 is alright but other module is over loading P.S. module. Insert M2, M3 &M4 one by one and find out which module is loading. Replace the fauttymodule. Confirm all D.C. Voltage are as per table No.1.

Step-6 : Proceed to check M2 as follows :

Please note that M3 should also be there. Put the selector switch (S3) inNominal set position and vary the Nominal set control to read 110V+ 10% on DPM. Set Nominal control to 110V. Now keep the selector switch(S3) to ’R’ set position and vary ‘R’ set control to read 104.5V to 109.5Von DPM. Set ‘R’ set control to 108V. Tum S3 to ‘L’ set position and vary ‘L’set control to read 110.5V to 115.5V on DPM. Set ‘L’ set control to 112V. If any ofthe settings are not obtainable, it means either front panel controls arefaulty or M2 is faulty. Replace M2. If problem still persists, then check frontpanel controls (i.e. potentiometers for their open/short conditions). Ifrequired replace them.

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Step-7 : Turn selector switch S3 to PT I/P position. Put NormaI/Test switch (S2) toTest position. Vary the Test control in clockwise direction to read PT I/P onDPM. If DPM does not read then measure AC Voltage at TP 3 w.r.t. GND onM2. It should vary from 0 to 5V AC. with clockwise rotation of Test Control.If the voltage is not coming, it means either S2 is faulty or 0-5V wdg. ofMains Tx. is open or Test control (CS) is faulty. If the voltage is,OK, itmeans M2 is faulty.

Step-8 : Vary the Test control & read PT I/P on DPM. When PT I/P is less than 88V(i.e. 80% of nominal set-UV levels), then the UV indication alongwith ’R’indication should come. Increase the voltage above 93.5V (85% of nominalset-UV restoration), then UV command goes “off”. However ’R’ commandremains “ON”. Increase PT I/P Voltage Slightly more than 108V, ‘R’ will gooff. This is B.W. Condition. Increase PT I/P Slightly more than 112V, ’L’indication should come. If the UV, L & R indications are coming as abovethat means M2 is 0K. If not change M2 After changing M2 still problempersists then check M3.

Step-9 : Proceed to check M3 as follows:

Set Time Delay (TD) control to 30 sec. Vary the test control to get ‘L’condition. Measure time from which ‘L’ indication comes to the time ‘LR’indication comes. The ’LR’ indication will remain ’ON’ for 2 sec. afterwhichonce again TD’ is initiated.

(The ‘TD’ indication is provided on M3) Similarly get ‘R’ condition, “RR”should come after set Time Delay. If ‘LR’ & ‘RR’ indications are notcoming after set time delay, it means M3 is faulty. In the ‘Test’ mode, thesupply to the relays is cut. Offer Hence relays will not operate onlyindications for ’LR’ & ’RR’ will come.

Step-10 : Put switch S2 to Normal position. In this position the PT I/P comesthrough rear panel (actual PT Voltage). Vary PT I/P and read on DPM. IfDPM does not read, measure AC Voltage at TP3 ON M2. It should bearound 3.3V AC for 110V AC PT I/P. If this voltage is not coming, it meanseither S2 is faulty or PT fuse is faulty or PT transformer on M2 is faulty.

Step-11 : To check relay module M4, vary PT I/P to get ’L & R’ conditions inNormal mode & confirm that Lower relay and Raise relay are operating,by checking continuity at rear terminals. If “RR” & “LR” indication arecoming but relays are not operating then check 15V supply to relayModule M4 or check S2. If relays are operating but 'NO’ contacts are notclosing means relay contacts are faulty. Ensure that Relay contacts arenot connected to the Tap-Changer Replace M4.

(In above description, it is assumed that DPM & LEDs are OK).

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Step-12 : TO CHECK DPM

Measure following voltages on DPM back side connector.

bet ‘0’ & 5V = 5V DC

bet Lo & Hi = 10V DC (approx) at 110 PT I/P

DPM should indicate 110.0V

If these Voltages are present and still DPM is not showing anything orsome segments or digits are not glowing it means that DPM is faulty,replace it.

For LEDs (mounted on front panel) : If M2 & M3 are OK and still LEDsare not glowing for proper conditions then the LED itself may be defective,replace it.

Table No.1 On Module-M1

Test Points Expected Voltage

betTP1 &TP3 +15V + 0.5 V

betTP2&TP3 -15V + 0.5 V

betTP4&TP3 +5V + 0.25V

betTP5&CapC8-ve +5V + 0.25 V

On Module - M2

Bet TP3 (on M1) & TP3 (on M2)(For PT I/P = 110VA.C.) 3.3VAC + 0.2%

Bet TP4 (on M2) & TP3 (on M1) (For PT input 110V +10VDC + 0.2%A.C.) (should vary with

PT input)

TP7 (on M2) & TP3 (on M1) (For Nom Set = 110V) +10V DC

Note : All the Voltagesare measured w.r.t. TP3 on module M1 .

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Potentiometer P1 on Module M2 is for adjusting UV settings. Factory set value is80% of nominal value. It can be adjusted upto 50% of nominal value.

Potentiometer P3 on Module M2 is for adjusting +10V DC at TP4 for PT input of110V A.C.

NATURE OF FAULT PROBABLE CAUSES

Unit not getting 'ON' Check fuses, 'Power On Switch Connectionsto rear connector are OK. Check M1. If faulty,replace it.

UV indication 'ON' Check PT supply, PT Fuse and M1.If all are OK, if faulty replace.

DPM reads '000' in all position of Checked M2, if faulty replace.selector switch S3

No Variation in DPM reading by varying Check M1 & M2, if faulty replace.R, L set controls or normal set controls

L or R or UV indications not coming after Check M1. If OK. M2 must be faulty.varying PT input beyond dead bandsettings.

L or R indication remains permanently 'ON' Check M2. If OK, M3 is faulty.

LR or RR not coming after varying PT I/P If M1 & M2 OK then M3 faulty.voltage and waiting for the set time delay.

Time delay LED on module M3 remains M3 faulty.'ON' permanently

Time delay is not as per set value Time delay dial might have shifted. Adjustthe setting of T.D. as follows. Slightly loosenthe Knob and rotate T.D. control fully anti-clockwise to match the dot with the startingdot below Tighten & check the Time Delayvalue for 30 secs. Readjust slightly ifnecessary.

LR & RR commands coming but OLTC If M1, M2 & M3 are OK and if Test/Normalnot operating switch is in Normal mode then replace M4.

If problem still persists then check-up controlpanel wiring.

'LR' or 'RR' commands remain "ON" If M1 OK, M2-OK then M3 faulty.permanently

IX. LINE DROP COMPENSATOR

I. DESCRIPTION

The Line Drop Compensator is an optional unit designed to match with the AutomaticVoltage Regulating Relay Type EE-301 M. The unit is housed in the same enclosure.(Plug-in type module)

The LDC unit cannot be mounted afterwards at site but has to be ordered at the time ofplacing an order.

The Voltage at the generating end and at the receiving end are not the same due to thedrop across the line. The LDC is used to compensate for this line drop, and the amountof compensation required is calculated as a % of the Nominal voltage knowing the lengthof the line, its resistance/unit length, its reactance/unit length and the rated current, andset on the front panel.

The line current is stepped down to 1Amp and fed to the LDC unit. The resistive andreactive drops are simulated by having 90° phase-shifted voltages and their polarity isselected by polarity switches. The net compensation is then summed with the steppeddown PT voltage.

II. SPECIFICATION :

Resistive Compensation : 0-20% of the regulating value continuously adjustable.Reactive Compensation : 0-20% of the regulating value continuously adjustable.Input rated current : 1 Amp, 50 Hz.Powerconsumption : 5VA max. at 1 Amp.Accuracy : 10%.Max. Over current : 50% of rated current (1.5Amp).PolaritySelection : Both positive and negative Compensation.

III. OPERATING AND CONNECTION INSTRUCTION:

Connections to the LDC unit are made through the rear panel terminals (5,6). The linecurrent is stepped down to 1Amp. 50 Hz and fed to the LDC. The net compensationis fed to the AVR ckt. internally.

The required amount of %R and %X compensation can be set on the front panel of theLDC. The polarity select switches will provide both positive and negativecompensation.

The %R & %X settings can be calculated from following formulae.

%X = Ö3ILxXL x 100 VL

%R = Ö3ILxRL x100VL

Where IL = the primary rated current of the line.

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VL = the voltage between lines of power transformer.

XL = the line reactance in ohms/phase.

RL = the line resistance in ohms/phase.

The LDC simulates the resistive & reactive drops across the line. The %R setting gives theresistive drop which is in phase with line current. The polarity switch VR selects whether thedrop has to be added or subtracted from PT Voltage.

In +VR position this voltage is subtracted from the PT voltage so that its effect on AVR is toRaise the voltage equal to the resistive drop to make the voltage at the load equal to nominaltvalue. In -VR position drop is added & its effect on AVR is to ‘LOWER’ the voltage. In normaluse, VR switch is kept on + posiiion.

The % X setting gives the reactive drop across the line. This drop is in phase quadrature tothe line current. The +VX gives lagging compensation and -VX gives leading compensation.Since the reactive compensation is in quadrature, its effect on AVR magnitude is very less.However, its effect is observable for power factors bet. 0.5 & 0.7 and is similar to VR compen-sation i.e. +VX raises the voltage & -VX Lowers.the Voltage.

The PT I/P to the AVR is internally stepped down to 3.3V corresponding to 110V. The vectorsum of resistive & reactive drops i.e. LDC 0/P is added vectorially to the stepped down PTvoltage to get the sense voltage at load end.

TESTING OF LDC

a) Feed 110V PT to AVR and keep R = 105 & L = 115.

b) Keep %R & %X setting of LDC to minimum position (i.e.U%)

c) Now the AVR is in dead-band condition. Feed 1A current through the terminals 5 & 6 on rearpanel.

d) Keep both polarity switches to +VR & +VX position.

e) Increase %R compensation trom 0 to 20%, 'Raise’ indication should come.

f) Put polarity switch to -VR position, “Lower” indication should come.

g) Bring back %R control to zero position.

h) Set R & L settings to 108V & 112V. lncrease % X control from 0 to 20%, Raise indicationshould come. Put polarity Switch to -Vx position, Lower indication should come.

(N.B.) - This can be observed only for a power factor of 0.5 to 0,7. For lower P.F. effect is notobservable.

Note :- If above tests are not ok, then interchange CT connections at 5 & 6 and carry outsame tests.

CALIBRATION CHECK OF %R

a) Assuming current in phase with voltage (i.e. P.F. = 1)

set L = 115V & R = 105V, %R = 0 & %X = 0.

Check operation of AVR without feeding 1Amp current to LDC.

b) Note down values at which R & L indications come. Let us say they come at 105V&115 respectively.

c) Pass 1 Amp current through LDC and increase %R setting to 5%. Put polarity switchesin + position.

d) Vary the PT Voltage and note value at which R & L indications come. They should be5.5V above set Values, i.e. R = 110.5V & L = 120.5.

e) Put VR switch to -Ve position and vary voltage and check the voltages when R & Lindication come. They should be 5.5V below the set values i.e. R = 99.5 & L = 109.5.Similarly check for 10% compensation. The difference will be +11V i.e. levels will beL = 126V, R = 116V, for +VR & L = 104, R = 94V for -VR.

f) The %X Compensation cannot be checked, because of its small effect on AVR. Ifabove tests are not coming OK, then change LDC unit.

VERY IMPORTANT

1. Do not remove LDC unit when C.T. current is flowing. (This action will make CT openCKT and damage it).

Arrange to switch off CT current or short CT before removing LDC unit.

2. When LDC is not to be used then both %X and %R dials should be kept at 0%. Thisposition will give 0 compensation. Do not remove LDC unit from relay as AVR will notfunction without LDC unit inside.

X. SUPERVISORY ALARMS OPTION

Following Supervisory Alarms options also can be incorporated in the same RelayEE 301- M, if required.

1 ) Relay contacts to give alarm instantaneously when Auxiliary supply to the AVR Relayfails.

2) Relay contacts to give alarm if the regulated voltage remains outside the set deadband for more than 15 minutes.

SUPERVISORY ALARMS

1) This unit consists of one relay which operates on 110V A.C. It remains energised aslong as 110V A.C. (Aux supply) is present at Pin No. 1 & 2 of the AVR relay. When Auxsupply fails, this relay gets deenergised, the “NC” Contacts at pin No.7 & 8 can operatethe alarm.

2) It also consist of a 15 minutes timer which starts counting as soon as the regulatedvoltage goes out of the set dead band (either Raise side or lower side). If the regulatedvoltage remains outside dead band for more than 15 minutes then a relay operateswhich closes “NO”’ Contacts at Pin 15 & 16. These contacts can be used for “Controlfail” alarm. The operation of this control fail relay is indicated by a red LED marked“CFR” mounted on front panel.

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This control fail alarm will operate in following circumstances:

a) failure of OLTC to raise or lower the taps.

b) incoming voltage very high or very low i.e. beyond control of the transformerand tap has reached either lowest position or highest position.

c) Mal-functioning of A.V.R. Relay.

The supervisor in the sub station should take appropriate steps to remove theabove mentioned faults.

If the voltage returns in the set dead band within 15 minutes, the 15 min timerresets automatically.

TESTING PROCEDURE

1) Give Aux supply 110V A.C. to the A.V.R. Relay and check continuity at Pin No. 7 & 8.It should show open. Remove Aux supply to the relay and check the continuity at PinNo. 7 & 8, it should show short.

2) CONTROL FAIL ALARM RELAY:

Make the dead band settings as desired. Change the PT voltage to get either R or Lindication. Keep the regulated voltage outside the set dead band; after 15 minutes(approx. ). the control fail alarm relay will operate and will remain in energised conditiontill the voltage returns to set dead band. This operation will be indicated by red LEDmarked CFR mounted on front panel of AVR Relay. The relay contacts can be checkedat Pin 15 & 16.

Take the regulated voltage within set dead band. The control fail Relay will getdeenergised and the contacts at Pin 15 & 16 will again become open and LED willstop glowing. Similarly this operation can be checked by taking regulated voltage onother side of set dead band.

XI LIST OF DRAWINGS :

1. Block Diagram : 01-ED-252. Front Panel View : 01-MD-293. Rear Panel View / Cutout

Dimensions/AVR connections : 01-MD-30

RECOMMENDED SPARES :

1. Power supply Mdule M12. Analog Card Module M23. Digital Card Module M34. Relay Module M45. Digital Panel Meter (DPM)6. Mains Transformer7 LDC Module (in case of AVR with LDC)

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WARRANTY

This product from EMCO ELECTRONICS is warranted against defects in materials andworkmanship for a period of 12 months from the date of despatch to the firstbuyer/purchaser of this equipment, this being essentially limited by warranties given toEMCO ELECTRONICS on the component used in equipment.

During the warranty period EMCO ELECTRONICS will at its option, either repair orreplace the product which prove to be defective provided the product has been usedwith reasonable care and in accordance with the manuals/product specification.Consequently this warranty shall also not apply to defects/damages in transit orresulting from misbehaving, misuse, Unauthorised modifications or repairs operationsoutside the environmental, electricai and/or other specification, improper or inadequatemaintenance of the product, or site conditions as required/recommended anddamages arising from accidental or abnormal causes.

The warranty period for items repaired/replaced shall not exceed then period for whichthe equipment was originaliy warranted and also the liability of EMCO ELECTRONICS tothe purchaser shall not in any case, exceeds the original purchase price of theequipment.

For warranty service or repair, the equipment must be returned to EMCOELECTRONICS securely packed on Freight paid basis and accompanied by acertificate stating that the equipment is being returned for warranty repairs and alsonote giving details of the purchase (Purchaser’s Name. and address, invoice No. andDate of purchase) and details of the equipment failure. faults conditions, other usefulinformation to faciliate early repair/rectification or the equipment.

Return of the equipment duly repaired can be arranged on payment of the packing andforwarding charges together with any cther taxes. duties, other miscellaneous expensesincurred, altematively the purchaser may arrange to collect the equipment from EMCOELECTRONICS. In case the repairs are not covered under warranty, the charges tor thesame must also be paid before collection of the equipment.

Our engineer’s services are available at site for instruments during warranty or out ofwarranty period, on chargeable basis. Details of which are available on request.

In the interest of development and improvement EMCO ELECTRONICS reserve theright to amend without notice details contained in this publication. No legal liabilitieswill be accepted by EMCO ELECTRONICS for any errors, omissions or amendments.

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To, From :EMCO ELECTRONICS106, Industrial Area,Sion (East), Mumbai-400 022.Tel. : 4096731 / 82

FAULT REPORTING FORM FOR AVR EE301-M

Please fill this form when sending the faulty AVR / Module for repairs. This will help us to serve you better.

AVR Serial No. :_________________ Supplied By :____________________________________

Working Since :__________________

Nature of problem :____________________________________________________________________________

____________________________________________________________________________________________

____________________________________________________________________________________________

Settings on AVR : L SET=_________R SET=_________NVA=__________TD=_________DPM Rdg. =___________

Check Auxillary & PT Fuses before proceeding.

Please observe the following on the faulty AVR & tick the appropriate box.

Put AVR in "TEST" Mode & vary the "TEST CONTROL" (TC.) Potentiometer.

Yes No

1. DPM rdg. varies with TC.

2. 'R' LED glows when DPM rdg.<R SET

3. 'RR' LED pulses after TD.

4. 'L' LED glows when DPM rdg.>L SET.

5. 'LR' LED pulses after TD.

6. 'UV' glows for UV condition.

7. ALL LEDs are off in Deadband condition.

Put AVR in 'NORMAL' Mode & check respective relay contacts.

8. 'RR' contacts close & open for step 3.

9. 'LR' contacts close & open for step 5.

10 'UV' contacts close (& open when UV restored) for step 6.

11. Any of the LR / RR / UV contacts permanently closed.

12. All 4 LEDs on M1 Module ON.

13. T1D LED on M3 Module loggles ON/OFF for continuous LR/RR conditions.

*Note : Open bottom front plate to observe the LEDs.

14. OPTIONS : LDC / CFR / AUXILIARY FAL operating properly.

15. Any other information :________________________________________________________________________

____________________________________________________________________________________________

____________________________________________________________________________________________

____________________________________________________________________________________________

NAME OF TEST ENGINEER :_____________________ SIGN. :___________________

DATE :__________________

DOC No. : SR 01-401/ISS-1

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